U.S. patent application number 09/975821 was filed with the patent office on 2002-07-04 for ultrasonograph.
Invention is credited to Muramatsu, Hiroyuki, Odagiri, Hiroshi, Shinogi, Masataka.
Application Number | 20020087082 09/975821 |
Document ID | / |
Family ID | 18831075 |
Filed Date | 2002-07-04 |
United States Patent
Application |
20020087082 |
Kind Code |
A1 |
Muramatsu, Hiroyuki ; et
al. |
July 4, 2002 |
Ultrasonograph
Abstract
An ultrasonograph capable of diagnosing a region of interest at
high sensitivity is offered. The ultrasonograph comprises a sensor
portion having a sending piezoelectric element for sending
ultrasound toward the radial artery and a receiving piezoelectric
element for receiving the ultrasound reflected from the radial
artery, a belt for holding the sensor portion from its back side
relative to the radial artery, and a processing portion for gaining
the pulse wave and the pulse rate in the radial artery based on the
reflected waves received by the receiving piezoelectric element and
displaying them. The belt is provided with a recessed portion that
is located opposite to the sensor portion and recessed relative to
the sensor portion. The space between the sensor portion and the
recessed portion functions as an ultrasound-attenuating
portion.
Inventors: |
Muramatsu, Hiroyuki;
(Chiba-shi, JP) ; Shinogi, Masataka; (Chiba-shi,
JP) ; Odagiri, Hiroshi; (Chiba-shi, JP) |
Correspondence
Address: |
ADAMS & WILKS
31st Floor
50 Broadway
New York
NY
10004
US
|
Family ID: |
18831075 |
Appl. No.: |
09/975821 |
Filed: |
October 12, 2001 |
Current U.S.
Class: |
600/459 |
Current CPC
Class: |
A61B 5/02438 20130101;
A61B 8/06 20130101 |
Class at
Publication: |
600/459 |
International
Class: |
A61B 008/14 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 27, 2000 |
JP |
2000-359292 |
Claims
What is claimed is:
1. An ultrasonograph comprising: a sensor portion having an
ultrasound-sending unit for sending ultrasound to a region to be
diagnosed and an ultrasound-receiving unit for receiving waves
reflected from the diagnosed region; a support unit for holding the
sensor portion from its back side relative to the diagnosed region;
an information acquisition unit for acquiring information about the
diagnosed region based on the reflected waves received by the
ultrasound-receiving unit; and an ultrasound-attenuating portion
for attenuating propagation of the ultrasound, wherein the
ultrasound-attenuating portion being interposed between the sensor
portion and the support unit.
2. The ultrasonograph according to claim 1, wherein the support
unit is provided with a recessed portion that is located opposite
to the sensor portion and recessed relative to the sensor portion,
and wherein a space between the sensor portion and the recessed
portion functions as the ultrasound-attenuating portion.
3. The ultrasonograph according to claim 1, wherein the
ultrasound-attenuating portion is an ultrasound-attenuating member
made of a material that attenuates propagation of ultrasound.
4. An ultrasonograph comprising: a sensor portion having an
ultrasound-sending unit for sending ultrasound to a region to be
diagnosed and an ultrasound-receiving unit for receiving waves
reflected from the diagnosed region; a support unit for holding the
sensor portion from its back side relative to the diagnosed region,
wherein the support unit having a holding portion against which the
sensor portion is held and an ultrasound-attenuating portion for
attenuating propagation of ultrasound through the support unit, the
ultrasound-attenuating portion being close to the holding portion;
and an information acquisition unit for acquiring information about
the diagnosed region based on the reflected waves received by the
ultrasound-receiving unit.
5. The ultrasonograph according to claim 4, wherein the
ultrasound-attenuating portion is a hollow groove formed in a
surface of the support member at a side of the sensor portion.
6. The ultrasonograph according to claim 4, wherein the
ultrasound-attenuating portion is a groove formed in the support
member and filled with a material that attenuates propagation of
ultrasound.
7. The ultrasonograph according to claim 3, wherein the material
that attenuates propagation of ultrasound is epoxy resin containing
powdered tungsten or a porous material.
8. The ultrasonograph according to claim 6, wherein the material
that attenuates propagation of ultrasound is epoxy resin containing
powdered tungsten or a porous material.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an ultrasonograph such as a
sphygmus (pulse wave) detection apparatus or ultrasonic
imaging-and-diagnosing system for sending ultrasound to a region to
be diagnosed (hereinafter often referred to as a region of
interest) and obtaining information about the diagnosed region
based on reflected waves and, more particularly, to an
ultrasonograph capable of diagnosing a region of interest at high
sensitivity.
[0003] 2. Description of the Related Art
[0004] Ultrasonographs for obtaining information about a biological
body or a substance using ultrasound have been well known for
years. Such an ultrasonograph emits ultrasonic waves to a region of
an examinee or substance to be diagnosed or examined, detects waves
reflected from the diagnosed or examined region, and gains
information about the diagnosed region based on the results of
detection. For example, in a sphygmus detection apparatus using
ultrasound, ultrasonic waves are emitted toward the radial artery
of an examinee, and the pulse waveform or the pulse rate is derived
from the amplitude of the reflected wave or from the variation in
the frequency.
[0005] One example of such an ultrasonograph is shown in FIG. 13
and has a sensor portion 600 equipped with an ultrasound-sending
unit and an ultrasound-receiving unit. The ultrasound-sending unit
is applied against a region to be diagnosed and emits ultrasonic
waves. The ultrasound-receiving unit receives reflected waves. The
side of the sensor portion 600 that is applied against the
diagnosed region and the opposite side are firmly bonded to a
support unit 100 such as a belt with an adhesive or the like.
[0006] In ultrasonographic diagnosis, the sensor portion 600 is
used while held against the surface of the diagnosed region of an
examinee or the like by the support unit 100. The sensor portion
600 is applied against the diagnosed region directly or via a layer
made of a material for acoustic matching such as silicon gel.
[0007] In this ultrasonograph, however, ultrasound is also emitted
toward the support unit 100 from the ultrasound-sending unit of the
sensor portion 600. The ultrasound sent toward the support unit 100
is reflected off the interface between the sensor portion 600 and
the support unit 100, propagates through the support unit 100, and
may be received as a noise signal by the ultrasound-receiving unit.
Sometimes, external ultrasonic noise may propagate through the
support unit 100 and be received by the ultrasound-receiving unit.
Where the ultrasound-receiving unit receives a noise signal in this
way, there arises the possibility that the detection sensitivity to
information about the diagnosed region based on the received
ultrasound is deteriorated.
SUMMARY OF THE INVENTION
[0008] Accordingly, it is an object of the present invention to
provide an ultrasonograph capable of diagnosing a region of
interest (i.e., a region to be diagnosed) at high sensitivity.
[0009] This object is achieved by an ultrasonograph in accordance
with a first embodiment of the invention which comprises: a sensor
portion having an ultrasound-sending unit for sending ultrasound to
a region to be diagnosed and an ultrasound-receiving unit for
receiving waves reflected from the diagnosed region; a support unit
for holding the sensor portion from its back side relative to the
diagnosed region; and an information acquisition unit for acquiring
information about the diagnosed region based on the reflected waves
received by the ultrasound-receiving unit. An
ultrasound-attenuating portion for attenuating propagation of the
ultrasound is interposed between the sensor portion and the support
unit.
[0010] An ultrasonograph in accordance with a second embodiment of
the present invention is based on the ultrasonograph in accordance
with the first embodiment described above and characterized in that
the aforementioned support unit is provided with a concave or
cutout portion which is located opposite to the above-described
sensor portion and concave when viewed from the sensor portion, and
that the space between the sensor portion and the concave portion
functions as the above-described ultrasound-attenuating
portion.
[0011] An ultrasonograph in accordance with a third embodiment of
the present invention is based on the ultrasonograph in accordance
with the first embodiment described above and characterized in that
the aforementioned ultrasound-attenuating portion is made of a
material that attenuates propagation of ultrasound.
[0012] The above-described object is also achieved by an
ultrasonograph in accordance with a fourth embodiment of the
invention which comprises: a sensor portion having an
ultrasound-sending unit for sending ultrasound to a region to be
diagnosed and an ultrasound-receiving unit for receiving waves
reflected from the diagnosed region; a support unit for holding the
sensor portion from its back side relative to the diagnosed region,
the support unit having a holding portion against which the sensor
portion is held and an ultrasound-attenuating portion for
attenuating propagation of ultrasound through the support unit, the
ultrasound-attenuating portion being close to the holding portion;
and an information acquisition unit for acquiring information about
the diagnosed region based on the reflected waves received by the
ultrasound-receiving unit.
[0013] An ultrasonograph in accordance with a fifth embodiment of
the present invention is based on the ultrasonograph in accordance
with the fourth embodiment, wherein the ultrasound-attenuating
portion described above is a hollow groove formed in a surface of
the support member that is on the side of the sensor portion.
[0014] An ultrasonograph in accordance with a sixth embodiment of
the present invention is based on the ultrasonograph in accordance
with the fourth embodiment, wherein the groove formed in the
support member is filled with a material that attenuates
propagation of ultrasound.
[0015] An ultrasonograph in accordance with a seventh embodiment of
the present invention is based on the ultrasonograph in accordance
with the third or sixth embodiment, wherein the material which
attenuates propagation of ultrasound is epoxy region containing
powdered tungsten or a porous material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a perspective view of a sphygmus detection
apparatus that is one form of an ultrasonograph in accordance with
the present invention, and in which the apparatus is worn on an
examinee;
[0017] FIG. 2 is a side elevation of the sphygmus detection
apparatus shown in FIG. 1, as viewed from the side of the shoulder
joint of the examinee when the apparatus is worn on the
examinee;
[0018] FIG. 3 is an exploded perspective view schematically showing
the structure of the sensor portion;
[0019] FIG. 4 is a cross section of the main portion of the sensor
portion as viewed from the longitudinal direction of the belt, and
in which the sensor portion is held to the belt;
[0020] FIG. 5 is a block diagram showing the structure of the
sphygmus detection apparatus shown in FIG. 1;
[0021] FIG. 6A is a cross-sectional view of the main portion of
other ultrasonograph in accordance with the invention, taken from
the longitudinal direction of the belt;
[0022] FIG. 6B is a perspective view of the main portion shown in
FIG. 6A;
[0023] FIG. 7 is a perspective view of the main portion of a
further ultrasonograph in accordance with the invention;
[0024] FIG. 8 is a cross section of the main portion of a still
other ultrasonograph in accordance with the invention, taken from
the longitudinal direction of the belt;
[0025] FIG. 9 is a perspective view of the main portion of an
additional ultrasonograph in accordance with the invention;
[0026] FIG. 10 is a perspective view of the main portion of a still
other ultrasonograph in accordance with the invention;
[0027] FIG. 11 is a cross section of the main portion of a yet
other ultrasonograph in accordance with the invention, taken from
the longitudinal direction of the belt;
[0028] FIG. 12 is a cross section of the main portion of a further
ultrasonograph in accordance with the invention; and
[0029] FIG. 13 is a perspective view of the related art
ultrasonograph.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0030] One embodiment of the present invention is hereinafter
described in detail by referring to FIGS. 1 to 5.
[0031] FIG. 1 is a perspective view of a sphygmus detection
apparatus that is one form of an ultrasonograph in accordance with
the present invention, and in which the apparatus is worn on an
examinee. FIG. 2 is a side elevation of the sphygmus detection
apparatus shown in FIG. 1, as viewed from the side of the shoulder
joint of the examinee when the apparatus is worn on the
examinee.
[0032] As shown in these FIGS. 1 and 2, the sphygmus detection
apparatus in accordance with the present embodiment is indicated by
numeral 1 and comprises a sensor portion 4 having a sending
piezoelectric element and a receiving piezoelectric element, a belt
50 acting as a holding unit for holding the back side (i.e., the
side of the sensor portion 4 facing away from the diagnosed region,
the side facing away from the ultrasound-sending portion from which
ultrasound is emitted toward the radial artery, and the side facing
away from the side applied against the examinee) of the sensor
portion 4 to the surface of the body outside the radial artery to
hold the sensor portion 4 relative to the radial artery, and a
processing portion 3 acting as an information acquisition unit for
gaining the pulse waveform and the pulse rate at the radial artery
based on the amplitude of the reflected waves received by the
receiving piezoelectric element. The sending piezoelectric element
of the sensor portion 4 acts as an ultrasound-sending unit for
sending ultrasonic waves to the radial artery that is a region to
be diagnosed. The receiving piezoelectric element acts as an
ultrasound-receiving unit for receiving the ultrasonic waves
reflected from the radial artery.
[0033] A space 62 acting as a portion for attenuating propagation
of ultrasonic waves is interposed between the sensor portion 4 and
the belt 50.
[0034] The sphygmus detection apparatus 1 in accordance with the
present embodiment is now described in further detail. As shown in
FIG. 2, the belt 50 is split into two parts 50b and 50c. The
processing portion 3 is connected between them. This belt 50 is
wound around the examinee's wrist, and both ends of the belt are
connected together by a fastening element 6. In this way, the belt
is held around the examinee's wrist.
[0035] The processing portion 3 is equipped with a display portion
33 that is placed on the outer side of the belt 50 when it is worn.
The sensor portion 4 is held against the inner surface 50a of the
belt 50 when it is worn. When the processing portion 3 is attached
to the left (or right) wrist 2 of the examinee on the hand's back,
it follows that the sensor portion 4 is placed almost just over the
radial artery 22 of the wearer and held there.
[0036] FIG. 3 is an exploded perspective view schematically showing
the structure of the sensor portion 4. FIG. 4 is a cross section as
viewed from the longitudinal direction of the belt 50 under the
condition where the sensor portion 4 is held to the belt 50.
[0037] As shown in FIG. 3, the sensor portion 4 comprises a lower
substrate 44 having electrodes (not shown) and an upper substrate
48 similar in shape to the lower substrate 44. The upper substrate
48 is placed over the lower substrate 44. A pair of piezoelectric
elements (a sending piezoelectric element 41 and a receiving
piezoelectric element 42) are held between the lower substrate 44
and the upper substrate 48 and in contact with the electrodes of
the lower substrate 44. The piezoelectric elements 41 and 42 are
sandwiched between the lower substrate 44 and the upper substrate
48.
[0038] As shown in FIG. 4, the belt 50 has a concave or cutout
portion 49 on one side of a thick-walled belt-like body, the
concave portion being recessed on the side of the opposite surface.
When the apparatus is worn, this concave portion 49 is on the side
of the inner surface 50a.
[0039] The fringes of the sensor portion 4 are bonded to the
periphery of the concave portion 49 in the belt 50 with adhesive,
and the sensor portion 4 covers the concave portion 49. Thus, a
space 62 is formed between the sensor portion 4 and the belt 50.
This space 62 acts as an ultrasound-attenuating portion for
attenuating propagation of ultrasound.
[0040] Any adhesive used to bond the sensor portion 4 to the belt
50 in the related art technique can be used without restriction as
the adhesive for bonding the sensor portion 4 to the belt 50. In
the present embodiment, glass is used as the upper substrate 48. It
is also possible to apply epoxy resin or other material having an
acoustic impedance midway between those of the human body and the
piezoelectric elements (PZT or the like), taking account of the
acoustic matching, instead of the upper substrate 48.
[0041] The sending piezoelectric element 41 receives a driver
signal and sends amplitude-modulated ultrasound of 32 kHz toward
the artery. Since the oscillation frequency is the same as the
oscillation frequency of the watch in this way, if the sphygmus
detection apparatus 1 is placed in the watch, the oscillator of the
watch can be used in common. If necessary, it is amplified and
delivered as an output. This can reduce the number of components of
the sphygmus detection apparatus 1 and hence the apparatus can be
fabricated inexpensively.
[0042] The sending piezoelectric element 41 and the receiving
piezoelectric element 42 are connected with signal lines (not
shown) buried in the belt 50 via the lower substrate 44 and the
upper substrate 48, respectively. In the present embodiment, the
sending piezoelectric element 41 and the receiving piezoelectric
element 42 are prepared separately. One piezoelectric element may
send, and the same piezoelectric element may receive reflected
waves to be received after a given interval. Furthermore, plural
piezoelectric elements or plural sets of piezoelectric elements may
be used.
[0043] FIG. 5 is a block diagram showing the structure of the
sphygmus detection apparatus 1 shown in FIG. 1.
[0044] As shown in this FIG. 5, the processing portion 3 comprises
a driver circuit 32 for sending out a driver signal that activates
the sending piezoelectric element 41, an arithmetic processing
portion 31 for processing the signal based on the ultrasound
received by the receiving piezoelectric element 42 to thereby
obtain pulse waveform and pulse rate, and a display portion 33 for
displaying the pulse waveform and pulse rate obtained by the
arithmetic processing portion 31.
[0045] The driver circuit 32 is equipped with an oscillation source
relying on an oscillator such as a quartz, and produces alternating
current of a frequency corresponding to the natural frequency of
the oscillator. High-frequency waves of 32 kHz are obtained by
frequency-dividing the frequency of the alternating current by a
factor of 2, 3, or so on. The high-frequency waves of 32 kHz are
sent to the sending piezoelectric element 41 via a signal line to
activate the sending piezoelectric element 41. This sending
piezoelectric element 41 sends ultrasound toward the surface of the
body of the wearer.
[0046] The arithmetic processing portion 31 detects the reception
signal from the receiving piezoelectric element 42 that receives
waves reflected from the radial artery, and creates a pulse-wave
signal based on the detected reception signal. The time intervals
between the peaks of the pulse-wave signal are measured such that
the number of measurements is 3, 5, 7, or 10, for example. The
number of pulses V per minute is found from the average time T of
the measured time intervals according to the following formula
(1).
V=60/T (1)
[0047] It is to be noted that the method is not limited to the
method of finding the number of pulses from the average time T
between pulse waves. For instance, the number of pulses w existing
within a given time interval t (e.g., 10 seconds) may be detected,
and the number of pulses V per minute may be found according to the
following equation (2).
V=w.times.(60/t) (2)
[0048] The pulse waveform and pulse rate obtained by the arithmetic
processing portion 31 are sent to the display portion 33, where
they are displayed. This display portion 33 is made of a liquid
crystal display to visualize the pulse waveform and pulse rate.
Alternatively, the pulse rate may be electrically displayed on a
panel.
[0049] The sphygmus detection apparatus 1 of the structure
described above is placed on the body surface during measurement of
pulse waves such that the sensor portion 4 is almost above the
radial artery 22. The apparatus 1 is held around the examinee's
wrist 2 by tightening the belt 50.
[0050] Under this condition, if the power supply of the sphygmus
detection apparatus 1 is turned on, the driver circuit 32 activates
the sending piezoelectric element 41, which then sends ultrasound
having a frequency of 32 kHz toward the radial artery 22. At this
time, the ultrasound from the sending piezoelectric element 41 is
also directed toward the outer surface but is attenuated and
absorbed by the space.
[0051] The ultrasound radiated toward the radial artery 22 is
reflected by the bloodstream through the radial artery 22. The
ultrasound is attenuated and amplitude-modulated by the
bloodstream. The degree of the amplitude modulation varies
according to the blood pressure. Therefore, the reflected waves
assume a waveform that is amplitude-modulated according to the
blood pressure.
[0052] The reflected waves are received by the receiving
piezoelectric element 42. Since the external ultrasound and so on
propagate to this receiving piezoelectric element 42 via the belt
50, those components which propagate toward the sensor from outside
the belt are attenuated and absorbed by the space 46.
[0053] In the receiving piezoelectric element 42, a reception
signal is created based on the received reflected waves. This
reception signal is sent to the arithmetic processing portion 31 of
the processing portion 3 via a signal line (not shown) from the
receiving piezoelectric element 42.
[0054] The arithmetic processing portion 31 detects the received
signal in the same way as in normal AM detection. That is,
rectification is done by a diode, and smoothing is done by a
capacitor. Then, a detection signal is obtained as the voltage
across a load resistor. Based on this detection signal, the pulse
rate is counted, and a pulse-wave signal is created.
[0055] The pulse rate and pulse-wave signal counted by the
arithmetic processing portion 31 are supplied to the display
portion 33, where the pulse rate and pulse-wave signal are
displayed. In the present embodiment, detection is done using AM
detection. The frequency of the reflected waves varied by the
Doppler effect of the bloodstream may be detected. In this case,
the arithmetic processing portion 31 needs to be modified
appropriately. In the present embodiment, a frequency of 32 kHz is
used. The used frequency is not limited to this. Any frequency
lying in the range of about 1 to 10 MHz may be employed.
[0056] In the sphygmus detection apparatus 1 in accordance with the
present embodiment in this way, a mounting portion for mounting the
sensor portion 4 of the belt is formed in a concave form.
Therefore, a space is formed between the sensor portion 4 and the
belt 50. Accordingly, ultrasound sent toward the belt 50 from the
sensor portion 4 is attenuated and absorbed by the space 62. As a
result, noise propagating from the sensor portion 4 to the belt 50
and received by the receiving piezoelectric element 42 is
reduced.
[0057] Furthermore, ultrasound passing into the belt from the
outside and traveling toward the sensor from outside the belt is
attenuated and absorbed by the space 62. Accordingly, the noise
received by the receiving piezoelectric element 42 is reduced in
this respect, too.
[0058] Since the amount of noise received by the receiving
piezoelectric element 42 is small, pulse wave information can be
detected at high sensitivity based on the received signal.
[0059] It is to be noted that the present invention is not limited
to the embodiment described above. Rather, various changes and
modifications may be made within the scope delineated by the
claims.
[0060] For example, in the above embodiment, the concave portion 49
is shaped into a form that is recessed one step from the outer
surface of the belt 50. The sensor portion 4 is firmly fixed to the
outer surface of the belt. The whole recessed portion 49
constitutes the space 62. It is to be noted that the shape of the
recessed portion 49 is not limited to this. As shown in FIG. 6, the
recessed portion 49 may be so shaped that it has an intermediate
step portion 49a. The sensor portion 4 may be mounted on this step
portion 49a. That portion of the recessed portion 49 which is
closer to the bottom than the step portion 49a may form the space
62. By burying the sensor portion 4 partially into the recessed
portion 49, the sensor portion 4 can be made to protrude by an
appropriate amount without limiting the thickness of the sensor
portion 4. The intensity of contact of the sensor portion 4 with
the diagnosed region can be set to appropriate degree. Hence, the
sensor portion 4 can be prevented from being applied against the
diagnosed region with excessive or insufficient force; otherwise,
the state of the diagnosed region would vary or the detection
sensitivity to reflected light would deteriorate.
[0061] In the above-described embodiment and its modifications, the
recessed portion 49 in the belt 50 forms the space 62. This space
62 acts as an ultrasound-attenuating portion. It is also possible
to fabricate the ultrasound-attenuating portion from a material
that attenuates propagation of ultrasound rather than from a space.
For example, the recessed portion 49 in the above embodiment may be
filled with epoxy resin containing powdered tungsten or a porous
member consisting of a porous material, and this is used as the
ultrasound-attenuating portion.
[0062] Furthermore, in the above-described embodiment and its
modifications, the recessed portion 49 is formed in the belt, and
the ultrasound-attenuating portion is formed by making use of this
recessed portion 49. The recessed portion 49 may not be formed in
the belt 50. As shown in FIG. 7, an ultrasound-attenuating member
60 made of a material that attenuates propagation of ultrasound may
be held between the linearly extending belt 50 and the sensor
portion 4, and this ultrasound-attenuating member 60 may be used as
the ultrasound-attenuating portion. By forming the
ultrasound-attenuating portion from the ultrasound-attenuating
member 60 held between the belt 50 and the sensor portion 4, the
ultrasound-attenuating portion is entirely interposed between the
belt 50 and the sensor portion 4 and so any portion of the sensor
portion 4 is not in direct contact with the belt 50. As a result,
it is assured that ultrasound propagating through the belt 50 is
attenuated and absorbed at the ultrasound-attenuating portion prior
to entering the sensor portion 4, as well as the ultrasound
reflected off the interface between the sensor portion 4 and the
belt 50. Examples of material that attenuates propagation of
ultrasound include epoxy region containing powdered tungsten and
porous materials.
[0063] In addition, in the above-described embodiment and its
modifications, the space 62 or the ultrasound-attenuating member 60
(ultrasound-attenuating portion) is interposed between the sensor
portion 4 and the belt (support unit) 50. An ultrasound-attenuating
portion for attenuating propagation of ultrasound through the belt
50 may be formed near the holding portion of the belt 50 to which
the sensor portion 4 is held, together with or instead of the space
62 or ultrasound-attenuating member 60. Examples of such an
ultrasonograph are illustrated in FIGS. 8-11.
[0064] The modified example shown in FIG. 8 is based on the
ultrasonograph shown in FIG. 6 and characterized as follows. The
portion of the recessed portion 49 that lies from the side of the
outer surface to the step portion 49a is made wider. The sensor
portion 4 is mounted to the center of the widened portion. A space
is formed between the outer surface of the recessed portion 49 and
the sensor portion 4. This space is used as an
ultrasound-attenuating portion (second ultrasound-attenuating
portion) 63 for attenuating propagation of ultrasound through the
belt. In this modified example shown in FIG. 8, ultrasound
propagating along the inner surface 50a of the belt is attenuated
and absorbed by the second ultrasound-attenuating portion 63. This
prevents propagation to the sensor portion 4. Inconsequence,
ultrasound noise produced by returning to the sensor portion 4
because of reflection at the interface between the sensor portion 4
and the belt 50 and noise entering the belt by reflection and
entering from the outside can be well prevented from being received
by the receiving piezoelectric element 42.
[0065] In the modified example shown in FIG. 9, the sensor portion
4 is firmly bonded directly to the belt 50 with adhesive. A groove
53 is formed around the holding portion 52 of the belt that holds
the sensor portion 4. The space within the groove 53 forms the
ultrasound-attenuating portion 63. In the modified example shown in
FIG. 10, the sensor portion 4 is directly firmly bonded to the belt
50 with adhesive. Grooves 53 extending across the belt 50 are
formed near the holding portion of the belt 50 which holds the
sensor portion 4. The spaces inside the grooves 53 constitute an
ultrasound-attenuating portion. The spaces may be directly used as
the ultrasound-attenuating portion. The spaces may also be filled
with epoxy resin containing powdered tungsten or a porous material
for attenuating ultrasound to form an ultrasound-attenuating
portion, in the same way as in other embodiments.
[0066] By forming the space 63 for attenuating propagation of
ultrasound through the belt (support unit) 50 near the holding
portion of the belt (support unit) 50 to which the sensor portion 4
is held as in the modified embodiment shown in FIG. 9 and the
modified embodiment shown in FIG. 10, noise entering the belt 50 by
reflection at the interface between the sensor portion 4 and the
belt 50 and noise entering from the outside are prevented from
propagating through the belt 50; otherwise, the noise would be
received by the receiving piezoelectric element 42. Hence, the
apparatus can diagnose the region of interest at high
sensitivity.
[0067] The modified embodiment shown in FIG. 11 is based on the
embodiment already described in connection with FIGS. 1-5 and
characterized in that a groove 53 extending across the belt 50 is
formed near the holding portion to which the sensor portion 4 is
held to make the space within the groove 53 the second
ultrasound-attenuating portion, in the same way as in FIG. 10. Also
in this modified embodiment, ultrasonic noise produced by returning
to the sensor portion 4 by reflection at the interface between the
sensor portion 4 and the belt 50 and noise entering the belt by
reflection and noise entering from the outside can be well
prevented from being received by the receiving piezoelectric
element 42, in the same way as in the modified embodiment shown in
FIG. 8.
[0068] In the above-described embodiments and modifications, the
recessed portion 49 is formed on the side of the inner surface 50a
of the belt 50 to which the sensor portion 4 is held to place the
ultrasound-attenuating portion between the sensor portion 4 and the
belt 50. Where the ultrasound-attenuating portion is placed between
the sensor portion 4 and the belt 50, one or more protrusions 55
may be formed on the side of the inner surface 50a of the belt 50
without forming the recessed portion 49 in the inner surface 50a of
the belt 50. The sensor portion 4 may be held to this protrusion
55. Thus, the space 62 may be formed between the sensor portion 4
and the belt 50. This space may be used as an
ultrasound-attenuating portion directly or by filling the space
with a material that attenuates ultrasound. Two such protrusions 55
may be formed across the belt, or may be cylindrical form such as
rectangular form whose dimensions are smaller than those of the
sensor portion 4.
[0069] In the above-described embodiments and modifications, the
ultrasonograph is a sphygmus detection apparatus. The
ultrasonograph to which the present invention is applied is not
limited to sphygmus detection apparatus. The ultrasonograph in
accordance with the present invention only needs to comprise: a
sensor portion having an ultrasound-sending unit for sending
ultrasound to a region to be diagnosed and an ultrasound-receiving
unit for receiving the ultrasound reflected from the diagnosed
region; a support unit for holding and supporting the sensor
portion from its back side relative to the diagnosed region; and an
information acquisition unit for acquiring information about the
diagnosed region based on the reflected waves received by the
ultrasound-receiving unit. For example, the ultrasonograph can be
an imaging-and-diagnosing apparatus for obtaining an image of the
inside of the human body by ultrasound, an ultrasonic flaw detector
for ultrasonically searching a building or the like for damages,
and various kinds of measuring instruments.
[0070] The aforementioned modifications can be used in combination
if necessary.
[0071] As described thus far, the ultrasonograph in accordance with
the present invention can diagnose a region of interest with
reduced ultrasonic noise and thus at high sensitivity.
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